Greenhouses are known. Typically, window glass for greenhouse applications is fabricated to meet several needs. These needs often include, for example, maximum visible light transmission, the scattering of unwanted infrared (IR) wavelengths to the shallow angles for their dissipation, and/or the scattering of the visible light components to steeper angles to provide their effective absorption by the plants.
Textured glass has been used for greenhouse windows. The textured morphology of the glass is normally achieved by chemical etching using HF-based solutions or by mechanical treatment, such as sand blasting.
Both chemical and mechanical treatments, however, often result in individual features of the textured surface having sizes on the order of tens or hundreds of microns. FIG. 1, for example, is an image showing the surface texture of chemically etched float glass. Unfortunately, this rather uniform sizing promotes considerable light scattering of all components of sunlight according to the laws of geometric optics. It is known, however, that the most useful wavelengths of sunlight in greenhouse applications are those between about 300-800 nm, which are responsible for morphogenesis. This includes those wavelengths between about 400-700 nm that are responsible for photosynthesis of the plants. Wavelengths that are greater than about 800 nm are considered parasitic by those skilled in the art because they are responsible for the generally unwanted increase in the greenhouse temperature.
Thus, it will be appreciated that it would be desirable to achieve a more preferential scattering of the IR components to the shallow angles and the visible light components to steeper angles relative to the glass substrate.
Certain example embodiments of this invention relate to a coated article comprising a coating supported by a substrate. The coating includes at least one thin-film layer that is textured so as to have surface features on the order of 0.3-3 microns that cause (a) light having a wavelength of greater than or equal to about 800 nm incident thereon to primarily scatter to angles less than 30 degrees relative to a major surface of the substrate and (b) light having a wavelength of less than or equal to about 700 nm incident thereon to primarily scatter to angles greater than 20 degrees relative to the major surface of the substrate.
Certain example embodiments of this invention relate to a coated article comprising a coating supported by a substrate. The coating includes at least one crystalline or polycrystalline thin-film layer that is textured so as to have micron- and/or sub-micron surface features that cause (a) light having a wavelength of greater than or equal to about 800 nm incident thereon to primarily scatter to angles less than 30 degrees relative to a major surface of the substrate and (b) light having a wavelength of less than or equal to about 700 nm incident thereon to primarily scatter to angles greater than 20 degrees relative to the major surface of the substrate.
Methods of making these and/or other coated articles are provided. For instance, certain example embodiments of this invention relate to a method of making a greenhouse window. A coating including at least one thin-film layer is disposed on a substrate. The at least one thin-film layer is textured so as to create surface features on the order of 0.3-3 microns, with the surface features being sized to cause (a) light having a wavelength of greater than or equal to about 800 nm incident thereon to primarily scatter to angles less than 30 degrees relative to a major surface of the substrate and (b) light having a wavelength of less than or equal to about 700 nm incident thereon to primarily scatter to angles greater than 20 degrees relative to the major surface of the substrate.
The features, aspects, advantages, and example embodiments described herein may be combined to realize yet further embodiments.